Spi 29-686-3 Class Zz Plus Plug Gage 0.686 in

Product Description

The SPI 29-686-3 is a Class ZZ Plus plug gage machined to measure bores and holes at a nominal diameter of 0.686 inches, with a tolerance of 0.0002 inches (0.0002 mm). Class ZZ Plus gages are used for go/no-go inspection of manufactured parts, confirming that a feature falls within acceptable dimensional limits. The steel construction provides durability and dimensional stability through repeated use. Machinists, quality control inspectors, and precision manufacturing professionals use this gage in production and inspection environments where tight dimensional control is required.

This gage is suited for shop-floor and inspection-room use in precision machining, tool-and-die, and manufacturing quality assurance operations. It is used to verify hole and bore dimensions on workpieces where the nominal target is 0.686 inches. The compact single-piece design makes it practical for bench inspection and inline production checks alike.

Key Features

• Nominal measurement diameter of 0.686 inches for consistent bore inspection
• Class ZZ Plus tolerance of 0.0002 inches ensures high-accuracy go/no-go checking
• Steel construction for wear resistance and dimensional stability
• Single-piece plug design for straightforward handling and use
• Compact and lightweight at 0.2 pounds for easy bench or inline use

Compatibility

Designed as an OEM-style replacement or standard plug gage for use with any go/no-go gage handle or fixture accepting a 0.686-inch diameter Class ZZ Plus plug insert in precision manufacturing and inspection applications.

Installation Notes

Plug gages are handled and used by machinists and quality control technicians — no installation in the traditional sense is required. Before use, clean the gage and the workpiece bore with a lint-free cloth to remove chips, oil, or debris that could affect measurement accuracy. Do not force the gage into a hole; apply light, consistent hand pressure to avoid damaging the gage or the part. Store the gage in a protective case away from moisture and abrasive materials to maintain calibration.